1. Field of the Invention
The present invention relates to a process cartridge and an image forming apparatus using the same, and more particularly to an effectively replaceable process cartridge and an image forming apparatus using the same.
2. Discussion of the Background
Image forming apparatuses include copiers, facsimiles, printers, plotters, multi-functional devices thereof, etc. Some image forming apparatuses may use an electrophotographic method to form an image on a recording medium. Such image forming apparatuses include a plurality of components such as a photoconductor drum, a developing roller, a charger, a cleaner, etc.
In consideration of size reduction or ease of maintenance, some image forming apparatuses are provided with a process cartridge for visualizing an electrostatic latent image on an image carrier with developer including toner. The process cartridge includes a plurality of components, and is configured to be detachably mountable to an image forming apparatus.
Such a process cartridge may be configured with a plurality of units. For example, a process cartridge may include a first unit having an image carrier, and a second unit having a developer carrier, which may be rotatably coupled to each other with a coupling member.
A process cartridge having such a configuration includes a photoconductor unit as the first unit and a developing unit as the second unit. The photoconductor unit also includes a photoconductor drum serving as an image carrier, while the developing unit includes a developing roller serving as a developer carrier. A coupling member for coupling the two units is disposed at a position in a direction in which an engaging pressure is applied between gears of the photoconductor drum and the developing roller. The coupling member is also supported so as to be movable along a direction perpendicular to the engaging pressure direction.
Thus, during driving of the photoconductor drum, the coupling member is positioned so as not to generate a rotational moment for unintentionally rotating the developing unit. Thereby the pressing force of the developing roller may be stably applied to the photoconductor drum to form a desired image.
Another conventional process cartridge having two units includes coupling pins for coupling the two units with each other. The two units are coupled so as to pivot around the coupling pins. The coupling pins are configured to project toward the outside of the process cartridge along the longitudinal direction of the two units.
Guide grooves are provided on an image forming apparatus using the process cartridge. When the process cartridge is mounted to or detached from the image forming apparatus, the coupling pins are put into or pulled out of the image forming apparatus along the guide groove.
For such a process cartridge, to reduce operating costs or environmental load, separate replacement of components is increasingly preferred to the whole replacement of the process cartridge as conventionally performed. Therefore a need exists for a process cartridge including replaceable components that are quick and easy to reuse.
However, a conventional process cartridge does not take sufficient consideration of the operability of components during disassembly and assembly thereof. For example, a process cartridge including coupling pins as described can be disassembled by clipping the end faces of the coupling pins with a tool. However, after disassembly, some time and effort are needed for re-inserting the coupling pins to reassemble the process cartridge.
In an image forming apparatus using a process cartridge as described above, a developing gap is formed between an image carrier and a developer carrier.
In a method of measuring such a developing gap, first, a measuring device is inserted into the developing gap, and a filling material stored in the measuring device is filled into and drawn from the developing gap. At this time, a portion of the measuring device expands and shrinks in the developing gap. The portion is provided with flat plates on both end surfaces thereof. The flat plates are brought into contact with both walls of the developing gap. Then the developing gap is measured with a detector of the measuring device.
In another method of measuring the developing gap, the developing gap is determined based on the width of a transmitting light flux measured by an optical dimension measuring device.
However, for the developing gap as described above, adjusting methods thereof are not sufficiently described compared to the measuring methods.